Design of a Monolithically Integrated High Speed (10Mbps) Optocoupler
Jelle H. T. Bakker · 2020
A new monolithically integrated optocoupler configuration is proposed that makes use of three stacked forward mode light-emitting diodes (FMLEDs) to reduce the energy loss over the series resistance of FMLEDs. These stacked FMLEDs do not require a high voltage (>5 V) external power supply. This is different from when an avalanche mode light-emitting diode (AMLED) is used because an AMLED requires at least a 5 V power supply. This thesis analyzes the design of the monolithically integrated optocoupler analytically. The design was verified using cadence simulations. The circuit blocks needed for the optocoupler have been designed to achieve bitrates of 10Mbps. The power supply for the transmitter is 3.3V; the receiver requires a power supply of 1.8V. The transmitter allows for a variable energy per bit with a maximum of 6nJ/bit. The area is calculated to be 0.05mm2, which is much less compared to reported state-of-the-art galvanic isolators based on capacitive (3mm2) or inductive coupling (30mm2).